Like it or not your going to get a lot of octave, fuzz and filter combos. I'm going with my IE Oxide into my IE Xerograph. Literally made for each other. I'm awaiting the Subterreana to arrive for the octave/synth. My EHX Micropog(octave up and dry signal) into my Pigtronix EP2 is pretty sweet too.

SA Multiwave Bass Distortion into the POG2 with all of the octaves mixed in. I use an expression pedal to increase the amount of distortion on the MWBD. It really adds a ton of harmonics and pulls the octaves apart in the mix beautifully. Add a little reverb or delay and it is one of the prettiest sounds a bass can make.

EHX Micro POG into either a Phase 90 or a Vortex Flanger (ideally with a little bit of drive afterwards)...gets very close to an 8/12 string sound. Lush, but not too much so, with soem subtle movement.